1. Field of the Invention
The present invention generally relates to an engine control system for a watercraft, and more particularly relates to a control system for a watercraft engine that uses a speed adjustment mechanism such as, for example, a throttle valve, to vary the engine's output.
2. Description of Related Art
Watercraft such as pleasure boats, fishing boats, or the like, use motors (e.g., outboard motors mounted on transoms) to provide power to propellers or other thrust generating devices to move the watercraft forward or backward. For example, an outboard motor typically incorporates an internal combustion engine mounted at the top of an outboard motor structure. The motor is coupled via gears and shafts or other linkages to a propeller or other thrust generating device that is disposed in a submerged position when the associated watercraft is floating on a body of water. When the engine is operating, the engine power is coupled to the propeller or other thrust generating device to cause the movement of the watercraft.
A typical outboard motor includes an air induction system to provide air to the combustion chambers of the motor. Also typically, the air induction system of the engine includes a throttle valve that regulates a quantity of air delivered to the combustion chambers of the engine in response to control by an operator of the watercraft. The regulation of the air delivered to the combustion chambers enables the operator to control the speed of the engine and thus to control the amount of power delivered to the propeller or other thrust generating device. Alternatively, engine may include another speed regulating device to control the speed of the engine by controlling the fuel delivered to the combustion chambers or by controlling the timing of the ignition of the fuel in the combustion chambers.
The watercraft can advantageously include a controller remotely disposed in a cockpit of the watercraft so that the operator can control the position of the throttle valve or other speed regulating device without being positioned by the outboard motor. Typically, the controller has a lever that is pivotally or slidably mounted onto a body of the controller so that the operator moves the lever with respect to the controller body to cause a responsive movement of the throttle valve or a corresponding change in an alternative speed regulating mechanism.
The controller lever may be coupled to the throttle valve by a mechanical linkage or by an electrical system. For example, the mechanical linkage may advantageously include a mechanical cable that couples the lever with the throttle valve so that movement of the lever is directly transferred to the throttle valve to cause movement of the throttle valve.
As a further example, an embodiment of an electrical system advantageously includes one or more wires (e.g., electrical cables or other conductors) and includes an electric motor disposed at the throttle valve. The movement of the lever is converted to an electrical signal that is transmitted to the electric motor, either directly or via a motor controller. The electric motor rotates in response to the electrical signal to cause the throttle valve to pivot in response to the movement of the lever. One skilled in the art will appreciate that the electrical conductors can be replaced with a fiber optic or wireless signal transmission systems.